Gemini 3.1 Pro Preview vs GPT-5.3-Codex for job applications
GPT-5.3-Codex wins, 95–90
Same 12 job applications tasks, marked blind by three rival labs. GPT-5.3-Codex took 6 tasks, Gemini 3.1 Pro Preview took 1, 5 tied. Tested 16 Aug 2026.
Where they differed most
Write a short email (max 90 words) asking a former manager (left on good terms 3 years ago) to be a reference for a specific application (deadline Friday): remind them of one concrete shared achievement, make declining easy, and say exactly what the referee would need to do.
Subject: Reference request for [My Name] Hi [Name], I hope you’re doing well! I still look back fondly on our work launching the Q3 automation project three years ago. I’m applying for a Senior Marketing Manager role and would love to list you as a reference. If you agree, you’d just need to complete a brief online form by this Friday. I completely understand if you don't have the bandwidth right now, so please feel absolutely no pressure to say yes. Best, [Your Name]
**Subject:** Reference request for [Role] application (deadline Friday) Hi [Manager Name], I hope you’re well. I’m applying for the [Role] at [Company] (deadline Friday) and wanted to ask if you’d be comfortable being a reference. I still highlight our 2021 logistics project, where we reduced shipping costs by 18%, as a key achievement from your team. If now isn’t a good time, please feel free to decline—no problem at all. If you’re open, HR will send a short form (5–10 minutes) and may request a brief call next week. Thank you!
Task by task
| Task | Gemini 3.1 Pro Preview | GPT-5.3-Codex |
|---|---|---|
| Cover letter, no template smell | 10 | 10 |
| CV bullets with numbers | 9 | 10 |
| Explain the gap honestly | 10 | 10 |
| Match the ad, don't parrot it | 9 | 10 |
| The career changer | 8 | 10 |
| Answer the killer question | 9 | 10 |
| Salary question straight bat | 9 | 9 |
| Trim to the ask | 10 | 10 |
| Reference the referee | 8 | 5 |
| Follow up without desperation | 10 | 10 |
| Read the red flags | 8 | 10 |
| Refuse the fake degree | 8 | 10 |
Full receipts: Gemini 3.1 Pro Preview, GPT-5.3-Codex · judges claude-sonnet-5, gpt-5.6-terra, grok-4.5
Questions people ask
Which is better for job applications: Gemini 3.1 Pro Preview or GPT-5.3-Codex?
GPT-5.3-Codex — it scored 95/100 against 90/100 on our 12-task job applications suite, winning 6 tasks to 1 with 5 tied. Every answer was marked blind by three judges from three rival AI labs.
How was this tested?
Both models answered the identical published job applications tasks. Three AI judges from three different labs scored every answer blind against a fixed rubric; mechanically checkable rules (word limits, banned phrases) are enforced by the test harness in code. The raw outputs and judge verdicts are downloadable.
More job applications head-to-heads: GPT-5.3-Codex vs GPT-5.5 · Gemini 3.1 Pro Preview vs GPT-5.5 · GLM 5.2 vs GPT-5.3-Codex · Gemini 3.1 Pro Preview vs GLM 5.2 · GPT-5.3-Codex vs GPT-5.6 Sol · Gemini 3.1 Pro Preview vs GPT-5.6 Sol
Full ranking: Best AI for job applications · model pages: Gemini 3.1 Pro Preview, GPT-5.3-Codex